to oxidize and to be oxidized , the same meanings?


by BaO
Tags: meanings, oxidize, oxidized
BaO
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#1
Aug4-06, 01:14 PM
P: 8
for example: Zn has more tendency to oxidize than Ag, orZn has more tendency to be oxidized than Ag?
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sdekivit
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#2
Aug4-06, 01:26 PM
P: 92
Quote Quote by BaO
for example: Zn has more tendency to oxidize than Ag, orZn has more tendency to be oxidized than Ag?
no they're not the same!

--> to oxidize = to take up electrons from a reducing agent
--> to be oxidized = lose electrons due to an oxidizing agent ( = to reduce)

Remember: an oxidizing agent gets reduced and a reducing agent gets oxidized.
BaO
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#3
Aug4-06, 04:51 PM
P: 8
so it should be like this right? : Zn has more tendency to be oxidized than Ag

BaO
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#4
Aug4-06, 04:53 PM
P: 8

to oxidize and to be oxidized , the same meanings?


wait! how come my book says Zn has more tendency to oxidize than Ag?
Cesium
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#5
Aug4-06, 05:04 PM
P: 274
Your book probably shows you an activity series that looks something like this: http://www.unr.edu/sb204/geology/mas.html. The higher up a metal is on that list the more readily it will be oxidized. The higher up a metal is on that list the stronger the reducing agent it is. The lower down a metal is on that list the more readily it will be reduced. The lower down a metal is on that list the stronger the oxidizing agent it is.

When you use "oxidize" as a verb, the subject of the verb is being reduced. The direct object of the verb is being oxidized. When you use "reduce" as a verrb, the subject of the verb is being oxidized. The direct object is being reduced.

Silver nitrate oxidizes zinc.

Silver nitrate is being reduced- it the oxidizing agent.

You could also say: Zinc reduces silver nitrate

Zinc is being oxidized- it is the reducing agent.
Gokul43201
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#6
Aug6-06, 01:48 AM
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Quote Quote by BaO
wait! how come my book says Zn has more tendency to oxidize than Ag?
That is wrong! Can you directly quote the passage/sentence where it says this?

What is the name of the book (and its authors)?
sdekivit
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#7
Aug6-06, 03:38 AM
P: 92
for the serie of metals in oxidation and reduction, a more nobler metal will always oxidize a less nobler metal.

--> thus Ag will oxidize Zn (you can also look this up in a table of standard electrode potentials)
Gokul43201
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Aug6-06, 09:59 AM
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Quote Quote by sdekivit
for the serie of metals in oxidation and reduction, a more nobler metal will always oxidize a less nobler metal.

--> thus Ag will oxidize Zn (you can also look this up in a table of standard electrode potentials)
Actually, this is not what a reduction potential table tells you. And in fact, Ag will not oxidize Zn (nor will Zn oxidize Ag). If you mix Ag and Zn, there will be no real chemical reaction at all; they will most likely form a nearly isomorphous alloy.

However, Ag+ will oxidize Zn, while Zn2+ will not oxidize Ag.
Cesium
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#9
Aug6-06, 11:37 AM
P: 274
Quote Quote by Gokul43201
Actually, this is not what a reduction potential table tells you. And in fact, Ag will not oxidize Zn (nor will Zn oxidize Ag). If you mix Ag and Zn, there will be no real chemical reaction at all; they will most likely form a nearly isomorphous alloy.

However, Ag+ will oxidize Zn, while Zn2+ will not oxidize Ag.
BaO: This explains why I used silver nitrate in my example.
BaO
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#10
Aug7-06, 02:21 PM
P: 8
how about this sentence , is it right?
magnesium has a higher tendency to oxidize than does iron?
sdekivit
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#11
Aug7-06, 02:42 PM
P: 92
Quote Quote by Gokul43201
Actually, this is not what a reduction potential table tells you. And in fact, Ag will not oxidize Zn (nor will Zn oxidize Ag). If you mix Ag and Zn, there will be no real chemical reaction at all; they will most likely form a nearly isomorphous alloy.

However, Ag+ will oxidize Zn, while Zn2+ will not oxidize Ag.
I disagree (as for the notation, i meant the ion Ag+).Of course you can see this in a table of standard electrode potentials:

[tex] Ag^{+} + e^{-} \longrightarrow Ag \Rightarrow E^{0} = +0.80 V[/tex]
[tex] Zn^{2+} + 2e^{-} \longrightarrow Zn \Rightarrow E^{0} = -0.76 V[/tex]

The relation with thermodynamics: [tex]\Delta G = -nFE[/tex] And because [tex] E = E_{ox} - E_{red}[/tex] E = +0,80 - -0.76 = +1.56 V (when p = p0 and the concentrations are 1M and T = 298 K) the free Gibbs energy is negative and thus the reaction [tex] 2Ag^{+} + Zn \longrightarrow 2Ag + Zn^{2+}[/tex] will occur spontaneously.

In general when E > +0.3 V there is a spontaneous reaction.
sdekivit
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#12
Aug7-06, 02:48 PM
P: 92
Quote Quote by BaO
how about this sentence , is it right?
magnesium has a higher tendency to oxidize than does iron?
you mean the ions rght, because the elementary metals won't oxidise. Then it also depend on the charge of the iron ion.

But because [tex]E^{0}[/tex] of [tex]Mg^{2+}[/tex] = -2.37 V and of the least oxidizing iron ion [tex] Fe^{2+}[/tex] is already -0.44 V the above statement isn't true.


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